Severe Sexual Abuse Reduces Frontoparietal Network Activity during Model-Based Reinforcement Learning Updates

Trauma and trauma-related disorders are characterized by altered learning styles. Two learning processes that have been delineated using computational modeling are model-free and model-based reinforcement learning (RL), characterized by trial and error and goal-driven, rule-based learning, respectively. Prior research suggests that model-free RL is disrupted among individuals with a history of assaultive trauma and may contribute to altered fear responding. Currently, it is unclear whether model-based RL, which involves building abstract and nuanced representations of stimulus-outcome relationships to prospectively predict action-related outcomes, is also impaired among individuals who have experienced trauma. The present study sought to test the hypothesis of impaired model-based RL among adolescent females exposed to assaultive trauma. Participants (n=60) completed a three-arm bandit RL task during fMRI acquisition. Two computational models compared the degree to which each participant’s task behavior fit the use of a model-free versus model-based RL strategy. Overall, a greater portion of participants’ behavior was better captured by the model-based than model-free RL model. Although assaultive trauma did not predict learning strategy use, greater sexual abuse severity predicted less use of model-based compared to model-free RL. Additionally, severe sexual abuse predicted less left frontoparietal network encoding of model-based RL updates, which was not accounted for by PTSD. Given the significant impact that sexual trauma has on mental health and other aspects of functioning, it is plausible that altered model-based RL is an important route through which clinical impairment emerges

Value Estimation and Latent-State Update-Related Neural Activity During Fear Conditioning Predict Posttraumatic Stress Disorder Symptom Severity

Learning theories of posttraumatic stress disorder (PTSD) purport that fear learning processes, such as those that support fear acquisition and extinction, are impaired. Computational models that aim to capture specific processes involved in fear learning have primarily assessed model free, or trial-and-error, reinforcement learning (RL). Although prior research indicates that aspects of model-free RL are disrupted among individuals with PTSD, models have yet to quantify and identify whether more nuanced, contextually driven learning is also disrupted. Given empirical evidence of aberrant contextual modulation of fear in PTSD, the present study sought to identify whether model-based RL processes are altered during fear conditioning among women with interpersonal violence (IPV)-related PTSD (n=85) using computational modeling. Several traditional models and a latent-state model that captured model-based RL were applied to skin conductance responses (SCR) collected during fear acquisition and extinction, and the latent-state model was identified as the best fitting model. Model-derived parameters from the latent-state model were carried forward to neuroimaging analyses (voxel-wise and independent component analysis) and results revealed that reduced latent-state related activity within visual processing regions uniquely predicted higher PTSD symptoms. Additionally, after controlling for latent-state update-related encoding, greater value estimation encoding within the left frontoparietal network during fear acquisition and reduced value estimation encoding within the dorsomedial prefrontal cortex during fear extinction predicted greater PTSD symptoms. Results provide evidence of disrupted model-based RL processes in women with IPV-related PTSD, which may contribute to difficulties revising fear and safety information. Future work should further assess model-based RL in PTSD

Reward-based reinforcement learning is altered among individuals with a history of major depressive disorder and psychomotor retardation symptoms.

Reward-based reinforcement learning impairments are common in major depressive disorder, but it is unclear which aspects of reward-based reinforcement learning are disrupted in remitted major depression (rMDD). Given that the neurobiological substrates that implement reward-based RL are also strongly implicated in psychomotor retardation (PmR), the present study sought to test whether reward-based reinforcement learning is altered in rMDD individuals with a history of PmR. Three groups of individuals (1) rMDD with past PmR (PmR+, N = 34), (2) rMDD without past PmR (PmR-, N = 44), and (3) healthy controls (N = 90) completed a reward-based reinforcement learning task. Computational modeling was applied to test for group differences in model-derived parameters - specifically, learning rates and reward sensitivity. Compared to controls, rMDD PmR + exhibited lower learning rates, but not reduced reward sensitivity. By contrast, rMDD PmR- did not significantly differ from controls on either of the model-derived parameters. Follow-up analyses indicated that the results were not due to current psychopathology symptoms. Results indicate that a history of PmR predicts altered reward-based reinforcement learning in rMDD. Abnormal reward-related reinforcement learning may reflect a scar of past depressive episodes that contained psychomotor symptoms, or a trait-like deficit that preceded these episodes

The complex interaction between anxiety and cognition: Insight from spatial and verbal working memory

Anxiety can be distracting, disruptive, and incapacitating. Despite problems with empirical replication of this phenomenon, one fruitful avenue of study has emerged from working memory (WM) experiments where a translational method of anxiety induction (risk of shock) has been shown to disrupt spatial and verbal WM performance. Performance declines when resources (e.g., spatial attention, executive function) devoted to goal-directed behaviors are consumed by anxiety. Importantly, it has been shown that anxiety-related impairments in verbal WM depend on task difficulty, suggesting that cognitive load may be an important consideration in the interaction between anxiety and cognition. Here we use both spatial and verbal WM paradigms to probe the effect of cognitive load on anxiety-induced WM impairment across task modality. Subjects performed a series of spatial and verbal n-back tasks of increasing difficulty (1, 2, and 3-back) while they were either safe or at risk for shock. Startle reflex was used to probe anxiety. Results demonstrate that induced-anxiety differentially impacts verbal and spatial WM, such that low and medium-load verbal WM is more susceptible to anxiety-related disruption relative to high-load, and spatial WM is disrupted regardless of task difficulty. Anxiety impacts both verbal and spatial processes, as described by correlations between anxiety and performance impairment, albeit the effect on spatial WM is consistent across load. Demanding WM tasks may exert top-down control over higher-order cortical resources engaged by anxious apprehension, however high-load spatial WM may continue to experience additional competition from anxiety-related changes in spatial attention, resulting in impaired performance. By describing this disruption across task modalities, these findings inform current theories of emotion-cognition interactions and may facilitate development of clinical interventions that seek to target cognitive impairments associated with anxiety

The Reliability and Validity of Response-Based Measures of Attention Bias

BACKGROUND: Attention bias to threat is a fundamental transdiagnostic component and potential vulnerability factor for internalizing psychopathologies. However, the measurement of attentional bias, such as traditional scores from the dot-probe paradigm, evidence poor reliability and do not measure intra-individual variation in attentional bias. METHODS: The present study examined, in three independent samples, the psychometric properties of a novel attentional bias (AB) scoring method of the dot-probe task based on responses to individual trials. For six AB scores derived using the response-based approach, we assessed the internal consistency, test-retest reliability, familial associations, and external validity (using Social Anxiety Disorder, a disorder strongly associated with attentional bias to threatening faces). RESULTS: Compared to traditional AB scores, response-based scores had generally better internal consistency (range of Cronbach’s alphas: 0.68–0.92 vs. 0.41–0.71), higher test-retest reliabilities (range of Pearson’s correlations: 0.26–0.77 vs. −0.05–0.35), and were more strongly related in family members (range of ICCs: 0.11–0.27 vs. 0–0.05). Furthermore, three response-based scores added incremental validity beyond traditional scores and gender in the external validators of current and lifetime Social Anxiety Disorder. CONCLUSIONS: Findings indicate that response-based AB scores from the dot-probe task have better psychometric properties than traditional scores